The series follows the exploits of the Impossible Missions Force (IMF), a small team of secret agents used for covert missions against dictators, evil organizations and (primarily in later episodes) crime lords. On occasion, the IMF also mounts unsanctioned, private missions on behalf of its members.

The identities of the higher echelons of the organization that oversees the IMF are never revealed. Only rare cryptic bits of information are ever provided during the life of the series, such as in the third season mission "Nicole", where the IMF leader states that his instructions come from "Division Seven". In the 1980s revival, it is suggested the IMF is an independent agency (as the FBI can only legally operate within the United States and the CIA can only operate outside the country).

Steven Hill as Dan Briggs and Martin Landau as Rollin Hand (in disguise) in the premiere episode, September 17, 1966.

The leader of the IMF is initially Dan Briggs, played by Steven Hill. As an Orthodox Jew, Hill had to leave on Fridays at 4 p.m. to be home before sundown and was not available until after dark the next day. Although his contract allowed for filming interruptions due to religious observances, the clause proved difficult to work around due to the production schedule and as the season progressed, an increasing number of episodes featured little of Dan Briggs. Hill had other problems as well. After cooperatively crawling through dirt tunnels and repeatedly climbing a rope ladder in the episode "Snowball in Hell," in the following episode ("Action!") he balked at climbing a stairway with railings and locked himself in his dressing room. Unable to come to terms with Hill, the producers re-shot the episode without him (another character, Cinnamon Carter, listened to the taped message, the selected operatives' photos were displayed in "limbo", and the team meeting was held in Rollin Hand's apartment), and reduced Briggs' presence in the five episodes left to be filmed to a minimum.[2] As far as Hill's religious requirements were concerned, line producer Joseph Gantman simply had not understood what had been agreed to. He told author Patrick J. White, "'If someone understands your problems and says he understands them, you feel better about it. But if he doesn't care about your problems, then you begin to really resent him. Steven Hill may have felt exactly the same way".[3]

Hill was replaced without explanation to the audience after the first season by Peter Graves playing the role of Jim Phelps, who remained the leader for the remainder of the original series and in the 1988–1990 revival.

Barbara Bain as Cinnamon Carter, 1969.

In theory, Briggs and Phelps are the only full-time members of the IMF. As the series was originally conceived, they would form teams made up of part-time agents who came from a variety of professions, choosing their operatives based on the particular skills necessary for the mission. In practice, however (especially after the first season), Briggs and especially Phelps would choose the same core group of three or four agents for every single mission, leading these regulars to be considered de facto full-time IMF agents. Still, many episodes also feature guest stars playing one-time additional agents who have special skills.

Landau was billed as a "special guest star" during the first season; he had been cast as a guest star for the pilot with the understanding that he would be one of four or five rotating guest star agents. His contract gave producers an option to have him "render services for (three or four) additional episodes". To fill the void left by Hill's Sabbath absences, producers wound up using Landau for more episodes, always as a "guest star". He eventually struck a deal to appear in all the first season's remaining episodes, but always billed as a "guest star" so that he could have the option to give notice to work on a feature film. Landau contractually became a series regular in season two.[4]

As actors left the series over time, others became regulars. Replacements often possessed the same skills as their predecessors. For example, "The Great Paris" (Leonard Nimoy), Hand's replacement in the fourth and fifth seasons, is also an actor, make-up artist, magician and "master of disguise." Also seen in seasons five and six is Dr. Doug Robert, played by Sam Elliott (according to White, the character was introduced as a replacement for Willy, but the idea was dropped once the producers realized how popular Willy was with viewers).

Cinnamon's "replacement" in season four was a series of guest stars, only one making more than one appearance: Lee Meriwether as Tracey. Season five saw the addition of Dana Lambert, played by stage and movie actress Lesley Ann Warren (billed as "Lesley Warren"). In seasons six and seven, the female member of the team was cosmetologist and mistress-of-disguise Lisa Casey (Lynda Day George), whose first name was only established in the 1988–1989 revival. She was replaced in a third of the total season seven episodes, during her maternity leave, by Mimi Davis, played by Barbara Anderson, who had just come from the show Ironside.[5]

Morris and Lupus were the only actors to last through the full run of the original series. Morris also appeared in two episodes of the revival series, in which the character's son, Grant Collier (played by Morris's real-life son, Phil Morris), is also an IMF agent.

Although a Cold War subtext is present throughout the series, the actual Cold War between the United States and the Soviet Union is rarely mentioned over the course of the series. (See, for example, the mission objectives for "The Trial" and "The Confession" in Season One.) However, in the early years, specific locations behind the Iron Curtain are named (such as Lubyanka prison in the episode "Memory") and many of the targets appear to be leaders of fictional Slavic countries. Major named enemy countries include the "European People's Republic" and the "Eastern European Republic". Additionally, real languages spoken in Eastern Europe are used. In the Season One episode "The Carriers," one of the villains reads a book whose title is the (incorrect) Russian Na Voina (About War); police vehicles are often labelled as such with words such as "poliiçia", and "poIiia", and a gas line or tank would be labelled "Gaz" which is a Romanian translation. This "language", referred to by the production team as "Gellerese", was invented specifically to be readable by non-speakers of Slavic languages. Their generous use of it was actually intended as a source of comic relief. Uniforms of the target regime frequently include peaked caps, jackboots, and Sam Browne belts, hinting at connections with Nazi Germany or the Warsaw Pact.

In 2004, Professor Douglas Little of Clark University published a lengthy academic article explicitly linking the TV series to CIA history: "Mission Impossible: The CIA and the Cult of Covert Action in the Middle East".[6]

The IMF is also assigned to bring down corrupt politicians and dictators of Third World countries uninvolved in the Cold War, such as a particularly brutal practitioner of apartheid, or corrupt Central or South American nations, as well as organized crime figures, corrupt businessmen and politicians in the US. In two different first-season episodes, the mission is to stop the revival of the Nazi Party in Germany. Both episodes had Rollin Hand (played by Jewish actor Martin Landau) impersonate a leading Nazi figure – Martin Bormann in one case – in a successful effort to stop the revival. In season two, Hand would successfully impersonate Adolf Hitler in another mission to stop the revival of the Nazi Party in Germany.

As noted in the reference work The Complete "Mission: Impossible" Dossier by Patrick J. White, many IMF missions were essentially assassinations in disguise. In the first-season episode "Memory," it is established that the unspecified government agency behind the IMF has forbidden it to commit outright assassinations "as a matter of policy." To get around this restriction, many missions instead involve the IMF setting up its targets to be killed by their own people or other enemies. A notable example is the second season two-part story "The Council," later released to European movie houses under the title Mission Impossible vs. the Mob.[7] This policy is not consistently followed; for example, in the first season's "The Legend," Briggs' original plan is to personally shoot Nazi rallying-figure Martin Bormann, which is foiled by the discovery of a dummy and a tape recorder in the "man's" sick room. Gunplay is relatively rare on the part of the IMF, as its methods are more sophisticated and subtle like those used by con men to fleece the gullible, although several episodes in the early seasons (for example, the second season episode "The Spy," as well as in the pilot episode) do show the agents shooting people when necessary (usually underlings or enemy soldiers).

During the fifth season, with Paramount executives having gained greater control, new producer Bruce Lansbury began to phase out the international missions. These were more expensive to film, often requiring sets to be purpose built, along with special costuming, etc., all of which was far less necessary for "domestic" settings. This would manifest itself the following year with the IMF battling organized crime in most episodes, though this season still featured more international forays than not. These gangland bosses are usually associated with a criminal organization called "The Syndicate," a generic organization, or its franchises. Generally when describing such assignments, the tape message notes that the target is outside the reach of "conventional law enforcement."

The objectives of such missions is usually simply to obtain evidence that might be admissible in court, often taking the form of tricking the mobsters into making a confession while being recorded. Manipulating the targets into killing one another became much less frequent as well. Lansbury also attempted to replace Peter Lupus, who was expressing dissatisfaction with his part at this time, with Sam Elliott. Over the course of the fifth season, Lupus' William "Willy" Armitage appeared in thirteen of its twenty-four episodes, to the outrage of fans who demanded Armitage's return.[8] By the end of the fifth season, Elliott was gone; he did appear in the first filmed episode of season six,[9] and Lupus remained in the last two seasons, with Armitage being given a larger share of screen time and more demanding duties.

Mission: Impossible is noted for its format, which rarely changed throughout the series. Indeed, the opening scenes acquired a ritualistic feel, befitting the "quasi-official" aura the program sought for the clandestine operations.

Each title sequence started with a fuse being lit. As the fuse burned across the screen, clips from scenes in the current episode were shown. This was followed by credits introducing the actors. Throughout the title sequence, only the show's theme song could be heard. In the fifth season, the series introduced an altered version of the show's theme song, coinciding with episodes with Dr. Doug Robert during that season. Though Dr. Doug Robert did not appear in subsequent seasons, altered versions of the theme song were played during the subsequent seasons.

Most episodes begin with the leader of the IMF getting the assignment from a hidden tape recorder and an envelope of photos and information that explains the mission.[10] The tape almost always begins with "Good morning/afternoon/evening, Mr. Briggs/Phelps." (The only exception is the first season episode "Action!", in which Briggs does not appear; Cinnamon Carter listens to the briefing.) Then it explains the situation and ends with "Your mission Dan/Jim, should you decide to accept it" or words to that effect, with a brief explanation of the mission. The listener is reminded, "As always, should you or any of your I.M. Force be caught or killed, the Secretary will disavow any knowledge of your actions."[11] The instructions on the tape were read by voice actor Robert Cleveland "Bob" Johnson. At the end of the instructions, Phelps/Briggs is notified, "This tape will self-destruct in five [or, occasionally, "ten"] seconds. Good luck, Dan/Jim." Then smoke would rise from the tape, and the instructions would be destroyed. In filming, the tapes were not actually destroyed; instead, smoke was piped into the tape recorder to create the illusion. In some initial episodes, however, self-destructing tapes were created by adding a chemical to the tape and blowing air onto it, forcing the chemical to react by crumbling. This method was abandoned due to cost.[12]

There were a few exceptions (especially in most of the Season One episodes) to the use of a tape and standard photos, including a record/darkroom motif (the Season One episode, "A Spool There Was", in which the recording [a phonograph record] would "decompose sixty seconds after the breaking of the seal" [it had been contained in an air-tight plastic envelope]) and most notably a vintage phonograph that automatically scratched its record into oblivion. In a few instances, instructions at the end of the tape would ask Briggs/Phelps, "Please dispose of/destroy this recording in the usual manner/by the usual means." Briggs/Phelps would then throw it in an incinerator or use other means to render it unplayable, causing the recording to go up in flames.

There were a handful of exceptions to the "messages from the Secretary." Sometimes, circumstances more or less force a team into action. This first occurred in the program's opening season, when a "syndicate" boss kidnaps and threatens to kill the teenage daughter of a friend of Briggs unless he removes a grand jury witness against the mobster from police protective custody. How this man knew Dan was capable of such a task was not explained.[13] The last such instance was very near the end of the series, when the survivors of a previous IMF operation (Season Six's "Casino") recognize a vacationing Phelps from security camera photos and kidnap him to force his team to retrieve evidence that a plea-bargaining mobster is about to turn over to authorities.[14]

In the fifth season, the producers experimented with the format by sometimes eliminating the taped briefing (and/or the team meeting in Phelps' apartment), starting the episode with the mission already underway. In a few other cases, a personal matter involving Briggs, Phelps or another IMF operative would result in an "off-book" mission being undertaken. After the first year, an entire season's worth of "tape scenes" were usually filmed all at once prior to production of the rest of the episodes, and the crew never knew which tape scene would appear with which episode until it was broadcast.[15]

Some tape scenes were re-used, with only minor changes to various insert shots and Johnson's recorded voiceover. In the first season, for example, the same tape scene was used for both "Wheels" and "Legacy". The only differences were that ‘The Voice On Tape’ gave a different set of instructions in each episode, and there was very briefly a different set of insert shots of the photographs which Dan Briggs is viewing. The cost-saving practice of recycling tape scenes continued throughout the series run; generally each season reused at least one tape scene. One particular tape scene, of Jim finding a tape in a parking lot attendant's hut, was actually used in three widely scattered episodes: "The Astrologer", "Recovery" and "The Vault".

Next would follow what White refers to as the "Dossier Scene". Briggs or Phelps would be shown in a fancy apartment, retrieving an oversized, leather-bound dossier folder from a locked drawer. Inside this folder were plastic-wrapped dossiers (usually featuring standard 8×10 "glossies" of the respective actors) of the available IMF agents. Briggs/Phelps would toss the selected agents' dossiers onto a table. According to White, most of the never-chosen dossiers were photographs of various series staffers and their wives, including Mr. and Mrs. Bruce Geller (the author reproduces one oft-rejected agent's photo and identifies it as actually being the executive producer.[16]) A contemporary article in TV Guide[volume & issue needed] claimed that many of the photos put aside in the "dossier scene" were of studio and network executives and that it was considered a measure of one's status in the studio and network hierarchies to appear there, but White makes no such statement.

In early seasons, the agents selected often included guest stars playing agents with skills not possessed by the usual team. A doctor, particularly a specialist in a condition known to afflict the target, was a common sort of "guest agent". In numerous early episodes, the IMF leader would choose only two or three team members, though at least one of the main credited cast members was always involved. One episode, "Elena," featured a team consisting of Rollin Hand and Dr. Carlos Enero (guest star Barry Atwater);[17] because of Landau's official status at that point as frequent guest star this meant that technically none of the series' regular players was involved. Almost as often, however, Briggs would choose all of the regulars, plus one, two, or even three others.

In later seasons, the team was much more stable, consisting of the regular cast for the season, and the use of guest agents became markedly less frequent. Numerous dossier scenes from the Peter Graves episodes feature Jim poring through the photographs, only to once again choose the series regulars that had just been shown in the opening credits. By the third season, the dossier scene had been deemed somewhat disposable, appearing only when needed to introduce a guest agent. The first mission submitted by the Secretary that did not have the dossier scene was the last mission of the second season, "The Recovery".

After a period of being seen only occasionally, the dossier scene was seen again frequently in season four, due to the lack of a regular female team member in that season. It was dropped entirely as of season five.

In the pilot episode, the recorded message states that the team leaders have unlimited resources and wide discretion in choosing their team. Who devises the plan is never made clear, although the team leader is often shown writing or making notes. Preparations and the necessary logistics were almost never shown, although they are generally implied by the scenes that depict various steps of the mission. It is implied that only a short period of time elapses from the initial assignment until the team is in the field. Early episodes occasionally showed more of the preliminaries. "Memory" features a montage of Dan Briggs training a guest agent to assume the role he will play in the mission. "Old Man Out, Part 1" includes a scene of Briggs approaching an operative (played by Mary Ann Mobley) in order to recruit her, meeting with resistance before he finally convinces her to join the mission.

In the third segment of the opening act, called the "Apartment Scene" by White, the team would next be shown convening for their final briefing in the leader's apartment. Although the series was shot in color, the apartment had a color scheme composed of black, white, and shades of gray, such that the apartment was sometimes referred to off-camera as the black-and-white room (Steven Hill once suggested that an American flag be placed on a wall of Briggs' apartment, but Bruce Geller vetoed it in order to maintain the color scheme[18]). Two exceptions are the first season episodes, "Operation Rogosh", when the team immediately springs into action to capture their target in a staged auto accident, and the aforementioned episode "Action!", where the team meeting took place in Cinnamon Carter's apartment.[19]

The Apartment Scene acted as a teaser. In discussing the plan and their roles in it, the team members would make vague references to preparations necessary for its successful execution while leaving most details undisclosed. This scene also demonstrated and thereby established credibility for various gadgets or ploys that were key to the plan, such as a TV camera hidden in a brooch, a miniature radio-controlled hovercraft, a chess-playing computer, a "mentalist" or sleight-of-hand act, or a trained animal. In addition, this scene would establish, or at least hint at, the specialties and roles of any guest-star agents. Team members posing questions about aspects of the plan or why an alternative was not considered provided the writers with an opportunity to offer explanations for what otherwise might have seemed plot holes. When summing up, Phelps would often stress the difficulties in the action they were about to undertake or some key element of the plan vital to its success, such as a deadline by which the mission had to be completed.

During the fifth season, the producers decided to drop the dossier scene and phase out the tape and apartment scenes. By the end of the season, however, it had been decided to keep the tape and apartment scenes, but the dossier-choosing scene was eliminated for the rest of the series run (this is White's version, but in fact episodes missing the tape and/or the meeting scenes were few). The 1980s revival reinstated the "dossier scene" in the first episode, when Phelps selects his new team, but since he keeps the same team in subsequent episodes, no subsequent dossier scenes were made.

The episode then depicted the plan being put into action. This almost always involved very elaborate deceptions, usually several at the same time. Facilitating this, certain team members are masters of disguise, able to impersonate someone connected to the target or even the target himself. This is accomplished with realistic latex face masks and make-up. Some impersonations are done with the explicit cooperation of the one being impersonated. Also bona fides would be arranged to aid infiltrating the target organization. In some cases, the actor playing the IMF agent also portrayed the person to be impersonated (this most frequently occurred during Martin Landau's tenure on the series, notably in the pilot) or the voice of the person being impersonated was dubbed. In other cases, a guest star would play the dual role of both the original and the imposter (Rollin, Paris, or Casey). Sometimes one or more IMF team members would allow themselves to be captured in order to gain more access to or knowledge of the organization they are infiltrating, either by conversing with the target or being held in a jail cell and hatching their plan there.

A few episodes of the early seasons showed the painstaking creation and application of these masks, usually by disguise and make-up expert Rollin Hand. This was later omitted as the series progressed and the audience presumably became familiar with the mechanics of the team's methods. In the 1980s revival, the mask-making process involved a digital camera and computer and was mostly automatic. Most episodes included a dramatic "reveal" (also referred to as the "peel-off") near the end of the episode in which the team member would remove the mask.

Various other technological methods are commonly used as well. The team would often re-route telephone or radio calls so these could be answered by their own members. Faked radio or television broadcasts are common, as are elevators placed under the team's control. In some missions, a very extensive simulated setting is created, such as a faked train journey, submarine voyage, aftermath of a major disaster, or even the taking over of the United States by a foreign government. A particularly elaborate ploy, used on more than one occasion, sees the IMF working to convince their target that several years had passed while the target was in a coma or suffering from amnesia. In one episode, the IMF even convince their target (an aging mobster played by William Shatner) that time has somehow been turned back more than thirty years and he is a young man again.

The team would usually arrange for some situation to arise with which the target would have to deal in a predictable way, and the team would then arrange the circumstances to guide the outcome to the desired end. Often the plans turn on elaborate psychology, such as exploiting rivalries or an interest in the supernatural. Many plans simply cause the target to become confused or erratic or irrational, lose self-assurance, lose trust in subordinates or partners, etc., so that either the target would do what the team wanted (by falling back on predictable acts of desperation), or else the target's subordinates would replace the target and then act according to the team's predictions. These various ploys would usually result in either information being revealed to the team, or the target's disgrace and discrediting, or both.

In many early episodes, the mission was to "neutralize" the target and it was made clear that the target is ultimately shot by his superiors, staff, or rivals, though this was usually not shown on screen. In later seasons, where the targets were usually organized-crime figures or similar, the goal of the mission is often simply to collect incriminating evidence not obtainable by "conventional law-enforcement agencies." The team is not above falsifying such evidence as a last resort.

Dramatic tension was provided by situations in which team members appear to be in danger of being discovered (especially before commercial breaks). Sometimes unexpected events occur that force the team to improvise. On occasion, an outside party or one of the targets realize what is happening and put the plan at risk.

William Read Woodfield and Allan Balter served as story consultants for the first two seasons. According to White,[20] Woodfield and Balter relied heavily on The Big Con, written by David W. Maurer, for their inspiration. Hence Briggs/Phelps became the "grifter-in-charge;" Rollin Hand and Cinnamon Carter were highly effective "ropers," and Barney Collier and Willy Armitage were experts at building and/or equipping "big stores." Woodfield and Balter later became producers of the third season. They did not last long and were dismissed for believing that executive producer Geller had no authority over them.

Several times the series deviated from the standard format. In one episode of the original series, a gangster kidnaps the daughter of a friend of Dan Briggs and forces him to abduct a witness against him. In another, a mistake causes Cinnamon Carter to be exposed and captured by the villains, and Jim Phelps has to prepare a plan to rescue her. Another episode featured Phelps on a personal mission, when he returns to his small hometown for a visit and finds a series of murders among his childhood acquaintances, which the local law enforcement chief is unqualified to cope with. In one episode, a friend of Jim Phelps is framed for murder, giving Jim only 24 hours to find the real killer, prove his friend's innocence and save his life. On two occasions, he is captured and the team has to rescue him. In the 1980s series, former IMF agent Barney Collier is framed for a crime he did not commit and the IMF team has to extricate him, leading to a reuniting of Barney with his son and IMF agent Grant Collier (played by real-life father and son Greg and Phil Morris). Willy is shot and captured in one episode, and captured and tortured by a drug kingpin in another. Paris is kidnapped and brainwashed in an attempt to get him to kill Phelps. Jim and Rollin are on a hunting trip when Jim is taken mysteriously ill. (It turns out the residents of a "Norman Rockwell" town are hired assassins, who attempt to poison Phelps when he stumbles on their secret.)

In most cases, the action lasted right up to the final seconds, with the episode ending in a freeze frame as the IMF team make their escape, another successful mission concluded. Most often they leave in a nondescript panel truck. A dramatic device frequently used at the end was the sound of a gunshot or a scream in the distance as the target is killed by his associates, while the IMF team make their getaway. In the 1980s revival, this format was altered with the addition of a tag scene showing the IMF team regrouping (often still in disguise) and walking away. From the middle of the second season onwards, Jim Phelps often makes a quip.

Aside from the now iconic main theme, as well as the motif called "The Plot" which usually accompanied scenes of the team members carrying out the mission, the background music would incorporate minimalist innovations of percussion such as simply a snare drum and cymbals to build tension during the more "sneaky" moments of the episodes (sometimes accompanied by a flute playing in low tessitura). These quieter passages would greatly contrast the more bombastic fanfares when a mission member is at risk of getting caught just prior to a commercial break.

The main theme was composed by Argentine composer, pianist and conductor Lalo Schifrin and is noted for being in 5/4 time. About the unusual timing, Schifrin declared that "things are in 2/4 or 4/4 because people dance with two legs. I did it for people from outer space who have five legs."[21] "The Plot" was also composed by Schifrin, who scored three episodes in the first season and went on to score at least one or two episodes for most of the other seasons (season two is the only one to have no Schifrin-scored episodes, in part because he was helping to launch Geller's new series Mannix).

Schifrin was awarded two Grammys at the 10th Grammy Awards for his work on the first series (Best Instrumental Theme and Best Original Score for a Motion Picture or TV Show).[22] He was also nominated for two Emmys (for the first and third seasons). Among the other composers to work on the series were Jerry Fielding, Walter Scharf, Gerald Fried, Richard Markowitz, Benny Golson, Robert Drasnin, and Hugo Montenegro. Gerald Fried worked on Mission: Impossible concurrently while working on the Star Trek television series and re-used the infamous "Star Trek fight music" in several Mission: Impossible episodes.

Although two albums of re-recorded music from the original series had previously been released under Schifrin's name, Music from Mission: Impossible (Dot, 1967) and More Mission: Impossible (Paramount, 1968) the original scores were not commercially available until 1992 when GNP Crescendo released The Best of Mission: Impossible – Then and Now[23] featuring five scores by Lalo Schifrin for the original series and five by John E. Davis for the revival (Schifrin also scored three episodes of the revival, including the premiere, but none were included.)

A key inspiration for Geller in creating the series was the 1964 Jules Dassin film Topkapi, innovative for its coolly existential depiction of an elaborate heist. Geller switched the story away from the criminals of Topkapi to the good guys of the IMF, but kept Dassin's style of minimal dialogue, prominent music scoring and clockwork-precision plots executed by a team of diverse specialists. Several episodes in fact show close-up shots of an agent's wristwatch to convey the suspense of working on a deadline.

One of the more controversial points of Geller's was his insistence on minimizing character development. This was done intentionally both because he felt that seeing the characters as tabulae rasae would make them more convincing in undercover work, and because he wanted to keep the focus on the caper and off the characters themselves. Geller would even veto the writers' attempts to develop the characters in the episodes. This is why, even after Geller was removed from the show, the IMF agents would only have one scene at Jim's apartment where they interacted, and they were rarely if ever seen in their "real" lives.

As a side effect of this, cast turnover was never once explained on the show. None of the main characters ever died or were disavowed in the original series, but a character could disappear between episodes without mention or acknowledgment. The 1980s revival, however, did kill off a main character on screen; Bruce Geller had died on May 27, 1978, in a plane crash in Santa Barbara, California, so he was unable to potentially veto the decision. Mimi Davis is the only character whose recruitment as an IMF agent shown on screen, although such a scene was filmed for Dana Lambert (Lesley Ann Warren) and discarded.[25] The 1980s revival otherwise stayed true to Geller's edict, with the occasional brief exception.

The producers of Mission: Impossible were sued for plagiarism by the creators of an ABC show called 21 Beacon Street. The suit was settled out of court. Geller claimed never to have seen the earlier show; Beacon Street's story editor and pilot scripter, Laurence Heath, would later write several episodes of M:I.[26]

Writer William Read Woodfield was a fan of David Maurer's nonfiction book about con artists, The Big Con (also an unofficial inspiration for The Sting), and many episodes are strikingly similar to cons described in the book.[27]

The tape scene is very similar to one described in the 1964 Nick Carter-Killmaster novel Saigon, published in December 1964 and repeated in the 1966 novel Danger Key (copyright registered in February 1966). In the novels, secret agent Carter receives a package from his boss which, when activated, plays a tape-recorded message that self-destructs after playing once.

Part of each episode's title sequence was highly unusual, as it was composed of a number of very short clips of key scenes from the subject episode. This was, and remains, very rare for series television. However, it was already being done as of the previous season on I Spy, which like Mission had the lighting of a fuse leading to it. The hand with the match was, until sometime in the sixth season, that of creator Bruce Geller; in the revival series, the hand belonged to Peter Graves, who was shown holding the match. Several British teleseries produced by Gerry Anderson and his then wife Sylvia Anderson, the contemporaneous Thunderbirds and the mid-1970s Space: 1999 (which starred M:I alumni Martin Landau and Barbara Bain) among them, also did this. The reimagined Battlestar Galactica TV series also used this device. The clips in the opening sequence were chosen to showcase dramatic moments in the upcoming mission, such as moments of surprise, moments of violence, or equipment in use. In particular, the first clip shown was often someone getting punched and/or knocked out. For the first two seasons, the closing credits showed clips from that mission in freeze frame. At the start of 1968, when Paramount took over from Desilu, the same clips were shown during the closing credits across episodes; later seasons eschewed that approach, featuring a freeze frame of the hand lighting the fuse.

Mission: Impossible is still recognized for its innovative use of music. Composer Lalo Schifrin wrote several distinctive pieces for the series. The visual cuts in the main title sequence were timed to the beats and measures of the theme tune—written in (unusual) 5/4 time—while an animated burning fuse moved across the screen. Most episodes included fairly long dialogue-free sequences showing the team members—particularly electronics expert Barney Collier—making technical preparations for the mission, usually to the accompaniment of another easily recognizable tune called "The Plot." Lalo Schifrin also wrote a theme piece for each main character and the sound track for each episode incorporated variations of these throughout. Even when an episode's score is credited to some other composer, Desilu's music supervisor Jack Hunsacker would re-edit it, adding Schifrin melodies from the library.[28] The series had great impact on film and TV music. Before Mission: Impossible, a common compliment was along the lines of "the score worked very well but never got in the way or called attention to itself." By contrast, Mission: Impossible was praised for the prominence of its music.

At 171 episodes, the original version of Mission: Impossible held the record for having the most episodes of any English-language espionage television series for over 35 years (about 10 more episodes than its nearest rival, the UK-produced The Avengers). Its record was broken during the eighth season of 24 in 2010.[citation needed]

In North America, Mission: Impossible received limited VHS format release in the waning days of video cassettes: There was a subscription through Columbia House; GoodTimes Home Video issued a sell-through version of Episode 3, "Memory" (under the multiply erroneous title "Butcher of Balkens"); and Paramount Home Video released twelve two-episode volumes of "The Best of Mission: Impossible," six tapes at a time, in 1996 and 2000. Twelve episodes were also released on Laserdisc.

CBS DVD (distributed by Paramount) has released all seven seasons of Mission:Impossible on DVD in Regions 1, 2 & 4. The first season of the 1980s revival was released in the fall of 2011, with the second and final season announced for spring 2012.

On December 11, 2012, Paramount released Mission: Impossible: The Complete Television Collection on DVD in Region 1. The 56-disc collection features all 171 episodes of the series as well as bonus features.[30]

In 1980, media reports indicated that a reunion of the original cast was in the planning stages, for a project to be called Mission: Impossible 1980. Ultimately this project was delayed into 1983 (with the working title suitably updated repeatedly) before being cancelled altogether due to one plot after another being deemed inappropriate and unacceptable.[32] In 1984, another proposed M:I reunion was to have been a theatrical film, titled Good Morning, Mr. Phelps (Mission: Impossible The Movie). Ultimately, the proposed large budget sank this project.[33]

In 1988, the American fall television season was hampered by a writers' strike that prevented the commissioning of new scripts. Producers, anxious to provide new product for viewers but with the prospect of a lengthy strike, went into the vaults for previously written material. Star Trek: The Next Generation, for example, used scripts written for an aborted Star Trek series proposed for the 1970s. The ABC network decided to launch a new Mission: Impossible series, with a mostly new cast (except for Peter Graves, who would return as Phelps), but using scripts from the original series, suitably updated. To save even more on production costs, the series was filmed in Australia; the first season in Queensland, and the second in Melbourne. Costs were, at that time, some 20 percent lower in Australia than in Hollywood. The new Mission: Impossible was one of the first American commercial network programs to be filmed in Australia.

According to Patrick White's book, the original plan was for the series to be an actual remake of the original series, with the new cast playing the same characters from the original series: Rollin Hand, Cinnamon Carter, et al. Just before filming began, White writes, the decision was made to rework the characters so that they were now original creations, albeit still patterned after the originals, with only Jim Phelps remaining unchanged.[34]

The new series was not a hit, but it was produced cheaply enough to keep it on the ABC schedule. The new M:I ultimately lasted for two years; the writers' strike was resolved quickly enough that only four episodes were actual remakes, which, along with the decision to change the character names and backgrounds, resulted in the series being considered a continuation of the original series, rather than simply a remake.

The original series formula described above was largely repeated in the second Mission: Impossible series of the 1980s, though the writers took some liberties and tried to stretch the rules somewhat. Most notably, by the time of the revival series, the Impossible Mission Force was no longer a small, clandestine operation, but larger in scale, with references now made to IMF divisions and additional teams similar to the one run by Phelps. One episode of the later series featured the only occasion in which a regular IMF agent was killed on a mission and subsequently disavowed. The 1980s series also had IMF agents using technology that nearly pushed the series into the realm of science fiction, such as one gadget that could record dreams, and another that allowed the IMF to change the surfaces (actually digital screens) of special playing cards to appear to be whatever cards the plan required.

The revived series included special appearances by several 1960s–70s IMF veterans, including Lynda Day George, and Greg Morris as Barney; Morris's son, Phil Morris, played Barney's son in the new series. Four guest stars from the original run all played targets here, Alex Cord, James Shigeta, and in the same episode, Barbara Luna and Australian Michael Pate.

IMF leader Jim Phelps, played by Peter Graves in the original series, has a supporting role in the first of these films, and is played by Jon Voight; none of the other films feature any characters from the television series, although Rogue Nation does involve the Syndicate, a recurring element of the TV show.

In 1979, game designer Scott Adams released Mission: Impossible, a text adventure game that placed the player in the role of a secret agent trying to save the world. Adams had failed to acquire the rights to the title, and the game was quickly reissued as Impossible Mission and later Secret Mission.[37] Beyond the title and the name "Mr. Phelps" being mentioned on the tape recording at the beginning of the game, it had no overt connection to the TV series.

The 1984 computer game Impossible Mission also featured a story in which the player takes the role of a secret agent who must stop an evil genius, but it also has no overt connection to the Mission: Impossible franchise, although the game's designer Dennis Caswell claimed that the title was chosen because "it was, at least, somewhat descriptive, and the obvious allusion to Mission: Impossible was expedient."[38]

In addition, two hardback novels for young readers were published by Whitman Books, both by Talmage Powell:

The Priceless Particle (1969)

The Money Explosion (1970)

Of the above, only the 1967 John Tiger novel featured the team as led by Dan Briggs; the rest all featured the Jim Phelps-era IMF.

Dell Comics published a Mission: Impossiblecomic book on a sporadic schedule that lasted from the mid-1960s to the early 1970s. Only five issues were published before the series was cancelled. The first four issues were original publications; the fifth issue was a reprint of the first.[39] In 1996, Marvel Comics published a single-issue Mission: Impossible comic which served as a prequel to the 1996 feature film.[40]

In 1968, the GAF Corporation of Portland, Oregon/Paramount Films released a View-Master (21 stereo pictures in 3 round discs) with a 16-page story booklet ..."Good morning Mr Phelps. The man you are looking at is Dr. Erich Rojak, the nuclear physicist who has been missing..."[citation needed]